The
dog tag is an
oblong piece of metal used for
identification by
military forces. Embossed upon the
US dog tag are the wearer's
name,
rank,
branch of service,
social security number,
blood type, and
religion*.
Dog tags are issued in pairs, on two chains. The primary chain is of a size to put around the neck, the secondary chain is a mere 4 inches long. The second dogtag is normally threaded onto the laces of the wearer's combat boots (suitably muffled if need be). If the wearer is dismembered, or their torso destroyed, the second dog tag will hopefully survive enough to identify the corpse.
*Many non-Christian (especially Jewish) members of the US military will have NO PREF listed as a religion, especially when stationed in the Middle East.